In DC (direct current) or LF (low frequency) plasma processing systems, arcs develop when charge builds up on a cathode. When the accumulated charge becomes large enough, an arc will occur from cathode to the anode or target material in the plasma chamber. Similarly in RF (radio frequency) plasma processing systems charge may build in areas of the chamber where there is a dielectric layer sufficient to support a charge. Again an arc will occur to discharge the accumulated charge on an element in the plasma chamber. If not extinguished quickly, arcs can be very detrimental to the plasma process and the quality of the processed film. All of these plasma processing systems, DC, LF and RF, are referred to herein as plasma loads.
There are numerous arc handling hardware techniques for extinguishing arcs in plasma loads. These techniques involve briefly interrupting power provided from the power supply to the plasma load. Some examples include shunting the current provided by the power supply away from the plasma load, dropping the voltage applied to the plasma load, reversing the voltage applied to the plasma load, switching voltage and current to accomplish one or a combination of the above techniques.
Most recently, arc management control has been added to arc handling as a technique to prevent arcs from occurring in plasma loads. One example of arc management is periodically interrupting or reversing power from the power supply to the plasma load. In effect the plasma load is periodically discharged to prevent arcs from occurring. This is very effective in reducing arcs, but slows the plasma process and raises the cost of the process.